157878509 has 4 divisors (see below), whose sum is σ = 164742816. Its totient is φ = 151014204.

The previous prime is 157878491. The next prime is 157878529. The reversal of 157878509 is 905878751.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 157878509 - 2¹⁶ = 157812973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (157878529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3432119 + ... + 3432164.

It is an arithmetic number, because the mean of its divisors is an integer number (41185704).

Almost surely, 2^157878509 is an apocalyptic number.

It is an amenable number.

157878509 is a deficient number, since it is larger than the sum of its proper divisors (6864307).

157878509 is an equidigital number, since it uses as much as digits as its factorization.

157878509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6864306.

The product of its (nonzero) digits is 705600, while the sum is 50.

The square root of 157878509 is about 12564.9715081253. The cubic root of 157878509 is about 540.4734177097.

The spelling of 157878509 in words is "one hundred fifty-seven million, eight hundred seventy-eight thousand, five hundred nine".